Mini Rec 25 hum in all channels and modes

[Addictedtokaos]

This just happened last week. I just got the Mesa 5 band Eq in and connected it to my loop. I was playing around with the settings and then I heard a few crackles and pops. I didnt think much of it as I had the volume very low at the time.

When I went to turn it up I noticed the amp had a strange hum that wasnt there previously.

This video is CH2 Modern, 25w, nothing plugged into the input and nothing in the loop. All settings at 12:00. Amp is plugged into a furman power conditioner.
https://youtu.be/RSXjszhoXu0

The hum is present in both channels and all modes. With or without the fx loop hard bypassed and with no input at all.

Ive tried swapping every preamp tube with 3 different good tubes. I also tried 3 different sets of EL84s. Also, i tried with and without FS cable plugged in.

Im going to call Mesa tomorrow, but was wondering if anyone had any ideas.

 

[elvis]

Seems fairly normal. You will want to plug a guitar into the input and turn the guitar volume all the way down so you don't have any input noise.

Incidentally, there is a switched jack for the FX loop. You may have joggled it and it may have some oxide on it. Try plugging and unplugging the FX send and returns several times to clean it up.

 

[Addictedtokaos]

Thanks for the advice.

As for a guitar plugged into the input, makes no difference. And I tried some deoxit in the fx jacks as well, no go.

Best way to describe the change. Before the problem the amp had a whooshing/low hiss sound which was acceptable and normal to me. Now, its like when you are trying to tune a radio in between stations.

 

[jmontgomery]

Read this page:
http://www.mesaboogie.com/support/faq.html#tn